Take a moment to think about what features, in your opinion, factor into making a game great.  What makes your list?  Do any of the following appear:  a game that is challenging? … that offers variety?  … that will leave you stumped?  … that will frustrate you?  If any of these made the list for you, I recommend downloading a copy of 5×5, a free game for Windows Mobile Professional handhelds and phones.

The premise of 5×5 is simple.  Turn all of the squares on the screen black.  Simple, right?  Read on!  First launch of 5×5 reveals a simple five square by five square game board.  The center squares are already black, in the arrangement of a + sign.  Anywhere you tap on the board will turn the five squares black, with the center square of the + being the one you tapped.  Still simple?  What would happen if your new + arrangement overlaps another square that is already black?  If you guessed that it would toggle it back to gray, then you are correct.  That’s where the challenge comes in, as you have to find the exact combination of black plus arrangements to turn the entire board black.  The screenshot below shows my best attempt so far!

Figure out the five square by five square board, and move on to a seven by seven square board.  The program includes a total of four different boards, including the previous two, a nine by nine board and an eleven by eleven board.

By now, you may be thinking that this sounds really simple.  There’s no way that you can have trouble solving this puzzle, right?  Go ahead, give it a try, after all with the price of free, it isn’t going to break your budget for the month.  Be warned though, 5×5 is a challenge.  You may even end up talking to your friends or spouse more as you bounce ideas of how to solve the puzzle off of them.  Don’t ask me though, I still haven’t figured it out!

You can download 5×5 here.  Please note that the zip file doesn’t include a CAB installer, only the application exe.  You can tap extract the exe to anywhere on your device and tap on it in Explorer to run the program.